Sound-reproducing system



June 24, 1930.

J. o. PRESCOTT r AL SOUND REPRODUCING SYSTEM Filed'Jan. '7, 1929 3 Sheets-Sheei l IIIM- F I ATTORNEY (III I June 24, 1930.-

J. o. PRESCOTT El AL 1,766,046 SOUND REPRODUCING SYSTEM Filed Janr'l', 1929 i s Sheets-Shee t 3 BY v @3 4/ ATTORNEY Patented June 24, 1930 ems "STATES JI't'JIBINPO. PRESCOTT, OF GLENBROOK, CONNECTICUT, AND FREDERICK A. KOLSTER, OF

PALO ALTO, CALIFORNIA, ASSIGNORS TO FEDERAL TELEGRAPH COMPANY, OF

NEWARK, NEW JERSEY, 'A CORPORATION OF CALIFORNIA SO'U'NI )-REIE?BODTJ'GING SYSTEM- Application filedJanuary 7, 1929. SerialNo. 380,952.

Our inventionrela'tes broadly to the reproduction of sound and more particularly to a'system for reproducing sound from a photographic sound record.

- One of the objects of our invention is to providea system or apparatus for sound re production in which a sound record is photographed in a spiral path upon ar'disk or plate whichis rotatably driven, and a light sensii e tive cell subjected to variations in light intensity in accordance with the movement of the sound record forcontrolling a sound reproducing system in accordance therewith.

Another object of our invention isvto provide a practical construction of sound reproducing system employing a photographic sound record which is encased in a protective enclosure and arranged to be rotatably driven for cooperation with a light sensitive cell Which'may be moved in a path for searching the photographic record.

Still-another"object of our invention is to provide a construction of closure for a disk shaped photographic sound record, which closure may bereadily mounted upon or removed from a phonograph operating in coop- I eration with a photoelectric cell and a searching device which may be moved at a speed proportional to the rate of rotation of the photographic sound record.

A further object 1 of our invention is to provide a mounting for a photographic sound record within a protective closure by which the photographic record may bedriven by the electric cell searching system for the reprodugtion ofsound from the photographic recor Other and further'objects off our invention reside in the construction of the photographic sound reproducing apparatus set forth in more detail in the specification hereinafter following and illustrated in the accompany: ing drawings wherein:

' through a phonograph. showing the mounting of the photographic record device of our invention thereon and illustrating the arrangement of the photoelectric cell search- 5 ing system which is driven adjacent thephousu'al phonograph with respect to a photo-' Figure 1 1s a cross sectional view taken tographic record; Fig. 2 is a cross-sectional view through the photographic sound record apparatus illustrated in Fig. 1 and showing the system of driving the photo-electric cell at a rate of speed proportional to the movement ofthe sound record; Fig. 3 is a frag mentary plan view of the casing which encloses the photographic sound record and illustrating the arrangement of the photoelectric cell searching device with respect to the sound record; Fig. 4 is a cross-sectional interiorly of the casing; Fig. 6' is a theoreti-' v cal view illustrating the manner in which the sound is photographed'on the photographic record; and Fig. 7 is a fragmentary view of a. portion of the photographic record illustrating the soundrecorded thereon in spiral paths.

The system of reproducing sound 1n accordance with our invention is to be distinguished from systems of sound reproduction now in use which employ a photographic film' strip on which a sound'record is recorded. We provide afiat disk on which the sound is recorded in a spiral path. Each sound record is carefully protected by an enclosing casing which closely conforms to the contour of the sound record and provides a support for the sound record which may be rotatably driven by mounting the record upon the rotatable shaft of a phonograph. We provide a mountinghaving a ph oto-electric cell and lightbeam projector which is driven laterally of the sound record at a speed proportional to the rate of rotation of the sound record for searching the record and controlling an electrical soundreproducing system.

Referring to the drawings 1n more detail,

'reference character 1 illustrates a phonograph in which there is housed a motor system' 2 havin a projecting shaft 3 which drives the spindle 4. A suitable hub 5 is positioned upon shaft 3 and serves to support thecasing which encloses the photographic sound record. The casing comprises a pair ion . ing having a I epending shoulder IOther-eon around which the portlon 6 of the casing 1s;

of thin sheet metal members 7 are united at their peripheries by an overlapping joint represented at 8 formin' a substantial-. 1y light proof casin buts ciently flexible to be readily separa le.- An annular frame member 9 is rovided interiorly of the casgripped. The upper face of the annular frame 9 is provided witha raceway-11 for ball-bearing members 12. An independentannular frame 14 is provided having an an-.

nul'ar raceway 15 thereon serving to cooperate with the ball-bearings 12. he annular frame 14. has an upstanding peripheral flange 16 thereon which rotates with concentric hub-- members 18 which grip the peripheral edge 19 of the photographic sound record 20. The

photographic sound record 20 isin the form of a dlsc of transparent material such as cel lulose or glass having a photo 'raphic record. thereon. A hub member 21 lsprovided at the center of the photographic sound record driven through spindle4. T e photo-electric- 20, and is arranged to be positively rotated by shaft member 3 by reason of the lock established throughkeyway 22. Suitable securing means such as'a nut member 23 may be providedfor cooperation with the hub member 21 v .for supporting the sound record 20. The lower portion of the casing at 6 rests upon frame 5 and remains stationary' thereon, while the sound record record interiorl of the'casing is cell is represented at 24 as housed" within a casing 25 from a rotatable member 27 at -one side of the phono aph. An arcuate shaped slot is provide at thelowerrwall 6 of the casing enabling movement of the hoto-electric cell directly ad'acent the soun record 20. The rotatablemem er 27 is journaled upon a bracket member 28 secured to one side of the phonograph-as represented at 29. A spindle 30:is journaled inbracket 28 and has a gear 31 at one end thereof meshing with a system 33,-in proportion to the speed 0 t of gears which are driven through a train of reduction gears, represented fgenerally at rotation 'of spindle 4. The'upper extremity of shaft member 30 is substantially. cone shaped, as

, An arm 36 exteiids'fromthe u sleeve 27 and hasa member 37 ries aligh beam projectin device represent;

represented at 34' and provides a frictiongrip with sleeve member 27, the frictional force being releasable bygneans of thumb screw 35. r portion of p inged thereto as represented at 38;. The member 37 ca-rf ed at .39 which-extends t rou ha slot 40 formed in'the'upper portion 0 casing 7 *en- I fjabling a? needle ray] of .lightfto be projected through the sound-record 20 andthrough the enclosing thesound record therein In testimony whereof we-afiiirgour'signatron tube: amplification system represented. at 42 which is coupled with any-deslred number "of stages of amplification represented at 43 for the control of loud speaker system 414 and-the reproduction of sound in accordance with the record on sound record20'.

It will be observed that the sound record is-readily removable from-the phonograph.

by elevating arm 37, removing the fiat casing and placinga new record thereon. Y

The arcuate shaped slots40 and 45 in the casings 6 and 7 are of such small size as not to permit entrance of dust, foreign matter 'or any substantial amount of light'to the soundrecord. v While we have described our lIlVGIltlOII 111 oneof its preferred embodiments, we desire that it be understood that modifications may be made and that no limitationsupon our invention are intended other. than are imposed o by the scopeof the appended claims.

What we claim as new and desire to secure by Letters Patent of the follows: i e

1. A sound reproducing system comprising a rotary mechanism, a casing arranged to be mounteddownwardly upon said rotary mech-. anism, an annular raceway ositioned around the interior periphery of said casing, a photographic sound record having its outer United States is as ery terminating in an annular mem er rotatable with respect to said raceway, a photoelectric cell projecting through one side of said casing toa position adjacent said photo;

' graphic sound-record, a light beam projecting device extending through the opposite side of said casing to a-position adjacent said photographic sound record, and means for'simul- 'taneouslyshifting said photo-electric cell and light beam projecting device at a speed proportioned to the rate of rotation of said photographic sound record.

2. In a sound reproducing system a casing com rising a pair of interlocked metallic lar member cooperating with said annular track and mounted for rotation with respect thereto, a central rotatable spindle and a photographic sound record mounted on said central rotatable'j spindle and said rotatableannular member,a photo-electric cell extends ing through one side of said casing to a position adj acen't'said photographic sound record and movable in proportion to the speed of rotation of said photographic soundrecord.

tures.

FREDERICK AL KoLs'rER.

JOHN O. PRESCOTT; i

. 11o mem rs, an annular track positioned inter s iorly of saidmetallic members adjacent" the j interior periphery thereof, arotatable annu- 

